Field
The present disclosure generally relates to radio-frequency (RF) signal combiners.
Description of the Related Art
Multi-mode/multi-band (MMMB) power amplifier modules (PAMs) useful for 4G LTE (Long Term Evolution) applications preferably operate in back-off to satisfy high peak-to-average-power ratio (PAPR) specifications while maintaining high power-added efficiency (PAE). Compared to envelope tracking PAMs for efficiency enhancement under back-off, Doherty PAMs are capable of meeting high efficiency with high linearity under back-off with much reduced system complexity and reduced calibration and digital pre-distortion (DPD) specifications. However, typical Doherty power amplifier architectures are bandwidth limited due to the narrowband nature of existing Doherty power combiners.